Carry over the mMaxPreWordCount when creating the new NgramContext

Change-Id: Iaba2e4b356486b60d550f10121695ef46e5e75da

java/src/com/android/inputmethod/latin/NgramContext.java

@@ -128,7 +128,7 @@ public class NgramContext {
         final WordInfo[] prevWordsInfo = new WordInfo[nextPrevWordCount];
         prevWordsInfo[0] = wordInfo;
         System.arraycopy(mPrevWordsInfo, 0, prevWordsInfo, 1, nextPrevWordCount - 1);
-        return new NgramContext(prevWordsInfo);
+        return new NgramContext(mMaxPrevWordCount, prevWordsInfo);
     }